Duramax, been running a Diablo sport predator for 4 years, 120 hp setting all the time unless towing anything over 5000 lbs or heavy in the hills. I took it out when i towed my WW 30' due to getting too hot. I did replace most of the motor and a new turbo after 80k punishing miles. Still run the tuner after almost a year on the new motor. Also I stacked a van aaken 70 hp box on top for a year prior to the motor letting go. No more stacking. And yep, replaced trans at 50k for burnt 4-5 clutches.
Dont do the crime if you cant do the time they say.
I have heard countless horror stories about the 6.0 and would not run a Banks over rated system.
Good luck and know anytime you arboosting the pressure from your turbo above what factroy specs are you run the chance of trans or engine problems. I am a gambler though, what can i say!